1. Field of the Invention
The subject matter described herein relates generally to power distribution systems and, more particularly, to an apparatus for locking out electrical protection devices.
2. Related Art
In power distribution systems, power is distributed to various loads and is typically divided into branch circuits, which supply power to the loads. The branch circuits include power distribution equipment such as transformers that step down the supply voltage for use by a load, e.g., a specific piece of electrical equipment.
Abnormal power conditions, such as faults, regularly occur in the power distribution system. These faults can cause severe damage to the system. To reduce or prevent damage, it is known to provide circuit protective devices to protect the various loads, as well as the power distribution equipment. One example of a circuit protective device is a circuit breaker that is employed to prevent high currents from being past to the load and/or the power distribution equipment in the event of a fault.
It is further known to utilize lockout mechanisms for circuit breakers that interact with the circuit breaker operating mechanisms to prevent the breaker contacts from being closed until the lockout mechanism is reset. Such lockout mechanisms also include solenoids having biased plungers that immediately return to their home position when the solenoid is de-energized.
Such lockout mechanisms suffer from the drawback of requiring manual intervention to reset the mechanism and enable the closing of the circuit breaker. These lockout mechanisms also suffer from the drawback of requiring continuous energizing of the solenoid to maintain the circuit breaker in the desired lockout state. In circuits having protection systems incorporating such mechanisms, loss of power and/or loss of communication within the protection system can result in unwanted changes to the lockout state of the breakers of the protection system. Such changes can occur regardless of the duration of the loss of power and/or loss of communication, and regardless of the extent of the loss of power and/or loss of communication throughout the system.
Accordingly, it is desired to provide an apparatus for locking out circuit protection devices that ameliorates the disadvantages and deleterious effects associated with prior art devices.